Question

An isloated point charge produce an electric field with magnitude E at a point 2 m away. At a point 1 m from the charge magnitude of the charge is .. A. E B. 2E C. 4E D. E/2

Answer 1

the correct answer is C, E’= 4E

Step-by-step explanation:

In this exercise you are asked to calculate the electric field at a given point

E =
`k (q)/(r^2)`

indicates that the field is E for r = 2m

E =
`( k q)/(4)` (1)

the field is requested for a distance r = 1 m

E ’= k \frac{q}{r'^2}

E ’= k q / 1

from equation 1

4E = k q

we substitute

E’= 4E

so the correct answer is C